Process for clarifying, decolorizing, and neutralizing oils



Patented Dec. 1 1, 1928.

UNITED, STATES 1,695,198 PATENT OFFICE.

DAVID R. MERRILL, OF BERKELEY, CALIFORNIA, ASSIGNOR TO UNION OIL COMPANYOF CALIFORNIA, LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

z PROCESS FOR CLARIFYING, DECOLORIZING, AND NEUTRALIZING OILS.

No Drawing. Application filed February This invention relates to the artof decolorizing, clarifying and neutralizing oils, fats, waxes andsimilar materials and While not necessarily limited thereto, moreparticu- 5 larly refers to such treatment of petroleum lubricating oils.The object thereof is to provide a process wherein the cost in time andoperations, as well as in materials, is considerably reduced, andwhereby a superior product is obtained. p

In the preparation of petroleum lubricating oils from fractions of crudepetroleum known as lubricating distillates, it is eommon practice totreat said distillates with sulphuric acid. This acid treatment effectsa considerable removal of coloring matter and other undesirablesubstances in the oil but does not sufiieiently decolorize and clarifythe oil for commercial purposes and in addition leaves the same in anacid condition thus rendering it unfit for use. It is necessarytherefore to subject the acid oil to a clarifying, decolorizing andneutralizing treatment. For decolorizing and clarifying the oils, thegenerally. accepted agent has been mineral earth such as fullers earthand clays, while for neutralization the practice has been to use sodiumhydroxide or other alkali. As to the decolorization and clarification, acommon method for oils, particularly petroleum lubrieating oils, hasbeen to percolate such oils through the fullers earth or other mineralearth; this method however has the disadvantage that it is tedious andnot highly effective. By other methods, the mineral earth in a finelydivided form is mixed with the oil, being later removed by filtration orother suitable means. The activity of most mineral earth when used in araw condition is not 4 high, and in consequence comparativelylargeamounts are required to obtain any suitable diminution of color. At thesame time the process is expensive not only because of the cost of theearth but particularly because of the large amount of oil left in theearth after filtration. To avoid the use of said large amounts of earth,various processes for aetivating the earth have been developed in orderthat a considerably smaller amount may be used to bring about a givencolor reduction. Such activation of the earth has usually been obtainedby acid treatment thereof followed by Washing with waterto remove theacid, and water-soluble reaction products, the earth eing u ed e t er nthe form of a mud 1, 1926. Serial No. 85,382.

or after drying and grinding thereof. This method of activation isexpensive not only because of the large amounts of acid and Waterrequired but also because of the large mechanical losses of earth duringthe washing and handling.

As to the neutralization of the oils with alkalis wherein the productsof neutralization have been separated by washing with water, the processpresents several disad vantages which can be related to the fact thatsome of the products of neutralization partake of the generalcharacteristics of soap and are active emulsifying agents. Because ofthe presence of these emulsifying agents the neutralization and Washingprocess involves considerable loss of oil, and if the temperatures ofoperation are maintained so high that the difiiculties fromemulsification are decreased an excessive reversion of color oftenis'experienced.

Because of the disadvantage of Wet neutralization processes, it has beengenerally considered that a dry neutralization process would be of'valueand many attempts have been made to utilize the absorptive propertiesofactive clays or fullers earth for this purpose. In general however,such treatment of acidoils does not give a product of satisfactorily lowacidity, unless either the or ganic acid content'of the oil be extremelylow or an excessive. proportion of earth be used. Such use of largeamounts of earth is expensive, both because of the cost of the earthitself and because of the losses of oil absorbed by the earth. Evidentlytherefore, it would be desirable to assist the neutraliz ing effect ofthe earth by the addition of reagents, and alkalis such as sodiumhydroxide, or alkaline earths such as lime, naturally present themselvesfor this purpose. However if a sufficient amount of alkaline material isused to neutralize the acid in the oil, it is found that considerableproportions of the products of neutralization are not removed by themineral earth but remain in the oil probably in a dissolved condition,and in consequence after removal of the earth by filtration or othermeans the oil has an excessive ash content. In other words the effect ofthe treatment is, to a considerable extent, merely to neutralize theacid impurities in the oil without removing them.

With my present process, a raw earth or clay is used and a considerabledegree of acti.

vation for decolorizing purposes is obtained at almost no additionalexpense over that of raw earth, and the amount of such clay isconsiderably reduced as compared with use of raw'earths as heretoforeproposed, while the neutralization step of this process, which employsclay and an alkali, results in the separation of the acid impurities tosuch an extent that the ash content of'the finished oil issatisfactorily low. The decolorizing and clarifying stage does notnecessitate the use of any additional equipment over that ordinarilyused with raw earth, and the amounts of reagents are so small that theadditional costs are almost negligible. Although the degree ofactivation obtained is sometimes not quite so great as in the usualmethods using large amounts of sulphuric acid, yet if the comparison ismade on the basis of equal amounts of raw earth originally taken, ratherthan on a basis of equal amounts of activated earth produced by the twoprocesses, it is found that the present method yields a verysatisfactory degree of activation and any difference in the degree ofactivation by the two methods is much more than compensated by the lowercost of the present method. The neutralization stage is accomplished bythe use of only moderate amounts of absorptive mineral earths ratherthan by the large amounts required when alkaline rcagents are not usedwith the mineral earth.

Briefly stated the invention comprises two stages of oil treatment andis applicable to either acid or neutral oil. The first stage, whichserves to decolorize the oil and remove the greater part of the mineralacidity along with a portion of the organic acidity, includes agitationof the oil with raw clay, water and added acid, the mixture beingheated, filtered and cooled. The second stage, which serves chiefly tocompleteneutralization, includes mixing the filtered and cooled oil withclay, water and an alkali such as sodium hydroxide and preferably withthe addition of sodium oxalate or some other water soluble compoundwhich forms diflicultly soluble calcium salts. This mixture is heated,filtered and cooled thereby yielding a neutralized product of excellentcolor and very low ash content. The invention resides further in thevarious steps. features and combinations thereof which will appear from.the disclosure of preferred forms herein presented.

Considering the preferred form of invention in detail, the first stageconsists in thoroly mixing from 4 to 20% of raw mineral earth in afinely divided state with the oil or fat to be treated, and adding tothis mixture an amount of dilute acid solution approximately equal inweight to half the amount of mineral earth used. While more or lesssolution may be added, it never should greatly exceed twice the Weightof the earth, and the 1 during mixing of the reagents in the oil andamount should preferably be so chosen as not to cause agglomeration orcoagulation of the mineral earth,-since, if such agglomeration orcoagulation takes place, the amount of active surface of the earth isdecreased and, in consequence, the decolorizing effect is diminished,unless special provision is made for breaking up the lumps andredispersing the earth in the oil. The acid solution which serves toactivate the clay when the mass is heated, consist-s preferably of anaqueous solution of a strong mineral acid or a strong organic acid inwhich the acid content is approximately equivalent to 4 mg. of potassiumhydroxide per gm. of oil to be treated, but the actual amount of acid tobe used will vary according to the amount and kind of mineral earthemployed, and the mineral acid content of the oil, if an acid oil isbeing treated. By the expression strong acid is meant 35 an acid eithermineral or organic which ionizes freely and serves readily to activatethe clay or other mineral earth, for which purpose the most satisfactoryacid has been found to be oxalic acid, although sulphuric acid yieldsapproximately the same final color and appears to be the best of themineral acids. Hydrochloric or phosphoric acid also may be employed, butusually these are not so satisfactory. Other strong organic acids whichmay be used are, for example, trichloracetic acid or maleic acid. Afterthe addition of the clay and of the acid solution, the mixture isheated, rapidly to a sufficiently high temperature to evaporatesubstantially all the added water, thereby to bring about activation andto give a satisfactory decolorizing effect. For this purpose atemperature approximating three hundred and twenty degrees Fahrenheithas been found very satisfactory although it is possible to usetempcratures both lower and higher but below the boiling point of theoil. The spent earth is then removed from the oil or fat by filtering,centrifuging or other suitable means, and, if this stage only is used,as for example upon a neutral oil, the product is cooled to atemperature not greatly exceeding atmospheric foixthe purpose ofpreventing reversion of color. However, if the oil is to be treated alsoby the second or neutralization stage to be hereinafter described. thecooling will be only to such a degree (e. g. 190 to 212 F.) as willavoid excessive evaporation the period of their reaction upon it.

The treatment just described results in clarification and decolorizationof the oil, and if the oil originally treated be an acid oil. thetreatment results also in partial neutralization.

This stage of the invention perhaps can best be set forth by means of anexample. To one thousand pounds of a petroleum lubricating oil, which asabove indicated may be either an acid oil or a neutral oil, there isadded eighty pounds of a finely pulverized fullers earth or otherabsorptive clay or mineral earth in a raw state. This 'earth or clay isthoroughly mixed with and distributed through the oil at a temperaturesomewhat but preferably not greatly in excess of ordinary temperature,as for example 120 F. for a viscous cylinder oil. To the mixture thereis then added with agitation about fifty pounds of an aqueous solutioncontaining two and one-half pounds of crystallized oxalic acid and aboutforty seven pounds of water. The temperature of the solution isunimportant, but should be maintained high enough to prevent separationof the acid in solid form. The mixture is then heated to about 320 F.steam being permitted to escape freely as it is formed and the earthbeing maintained in suspension by agitation or otherwise. The earth isthen separated from the oil by filtration, centrifuging or the like, andthe oil is cooled to a temperature below that at which the reversion ofcolor is rapid. By operating as in thisspecific example, the improvementin the quality of typical petroleum lubricating oils may be as follows:

Color, from No. 6 N. P. A. to No. 4 N. P. A.

Acidity, from an acid'number of 5 to 1, or in another example from anacid number of 0.15 to 0.03; p

Clarity, from cloudiness to substantial brilliancy.

The amount of acid used aboveapproximates one-quarter per cent, beingequivalent to an acid'number of 2.2 based on the oil.

This amount has been found to be very desirable and at the same timeprobably it is the most satisfactory generally, but it is observed thata somewhat greater amount of acid is used in treating neutr'aloil-thanin treating acid I oil. However, smaller or greater amounts may be used,approaching even two per cent, which represents an acid number of 23 forsulphuric acid and of,18 for oxalic acid, but such large amountsordinarily are not used.

The neutralization stage follows the above treatment and serves as wellto further clarify and improve the color of the oil. This step comprisesthoroughly mixing material amounts of raw mineral earths (usually fromfour to sixteen per cent) in a finely divided state' with the oil or fatto be treated, and adding to this mixturean amount of dilute alkalisolution approximating half the weight of the mineral earth used. Thedilute solution of alkali preferably consists of an aqueous solution ofsodium hyroxide containing alkali somewhat in excess of that equivalenttolthe acid content of the oil or fat to be I treated. As an alternativeform, this caustic alkali solution may contain certain salts, since"nution of the ash content of the finished product, these salts inparticular being sodium salts of comparatively strong acids which formdiflicultly soluble calcium salts, for example sodium oxalate and sodiumfluoride.

The actual amount of alkali and of these salts to be used will vary inparticular cases according to the acidity of the material to be treatedand according to the amount and kind of mineral earth employed. Ingeneral, the greater the amount of earth used, the greater should be theexcess of alkali over the amount equivalent to the acid content. Theamount of salts is preferably increased with the amount of alkali, sincein this way the greatest diminution in the ash content is obtained. Theamount of alkali solution is preferably so chosen as not to causeagglomeration or coagulation of the earth, since if such takes place theamount of active service of the earth is decreased, and in consequencethe decolorizing effect of the earth is diminished and the neutralizingeffect of the added alkali is also materially decreased, unless specialprovision is made for breaking up the lumps and redispersing the earthin the oil. After the addition of the earth and of the alkali solution,the mixture is heated rapidly to a sufiiciently high temperature (forexample 320 F.) to evaporate substantially all of the added water, andto produce the desired absorptive effect of the mineral earth. The spentearth is then removed by filtration, centrifuging or the like, and theoils cooled to a tem perature not greatly exceeding atmospherictemperature in order to prevent reversion of color.

As an example of this neutralization stage, to one thousand pounds of apetroleum lubricating oil such as supplied by the first or decolorizingstage heretofore described,there is earth or clay, in the raw state. Theearth is thoroughly mixed and distributed through the oil at atemperature preferably somewhat in excess of ordinary temperatures, butless than the boiling point of the aqueous solution added to the oil,for example 160 F. for a viscous cylinder oil. To the mixture is thenadded, with agitation, aboutaforty pounds of anaqueous solutioncontaining sodium hy-' droxide and sodium oxalate. If the oil beingtreated has an acid number of one milligram of potassium hydroxide pergram of oil, the solution will consist of about one pound of sodiumhydroxide, one and two-third pounds of sodium oxalate and about thirtyseven pounds of water. The temperature of the solution is unimportant.The mixture is then heated to 320 F., the steam being permitted toescape freely as it is formed, the earth being kept in suspension byagitation or otherwise. The earth is then separated from the oil as byfiltration or centrifuging and the oil cooled added eighty pounds of. afinely pulverized fullers earth or other absorptive mineral to atemperature below that at which reversion of color is rapid. Accordingto this specific example, improvement in the quality of a particularpetroleum lubricating oil may be as follows Color, from No. 5 N. P. A.to No. 4 N. P. A.

Acidity, from an acid number of 1.0 to 0.1.

Clarity, from cloudiness to substantial brilliancy, with an ash contentof the product of 0.005 per cent.

The amount of caustic alkali in the form of sodium hydroxide as givenabove approximates 0.1 per cent but for various oils other amountsthereof may be used up to about 0.5 per cent. The amount of sodiumoxalate may e varied according to requirements up to a maximum of aboutfour times the quantity of the sodium hydroxide. It is to beparticularly noted that the alkali solution preferably should be fairlydilute for the reason that it has been found that when the requiredamount of alkali is added as a dilute solution the ash content in theproduct is materially lower than when the alkali is added in moreconcentrated form. The quantities of solutions and the concentrationthereof must be determined, at least in most instances, with this factin mind. Thus the employment of an oxalate for the purpose ofprecipitating the calcium, together with the employment of dilute alkalisolution, serves to produce a product of satisfactorily 10w ash content,this content with many oils being unusually low. While the amount ofalkali solution usually approximates half that of the clay, it may beincreased but not to greatly exceed twice the weight of the clay.

According to the preferred method of operation, the two stages, whichfor convenience may be respectively referred to as the decolorizingstage and theneutralizing stage are both being used in the propersequence upon average oils to produce a satisfactory marketable productof good clarity, 00101 and low ash content, the first stage serving todecolorize the oil and remove the greater part of the mineral acidity,and the second stage completing neutralization. However where theorganic acid content of the oil is uite low, the decolorizing stagealone may e relied upon for neutralizing the'oil as well as fordecolorizing'and clarifying the same. Likewise an oil of. good color andintermediate acid content might be treated by the second or neutralizingstage alone, since this step will produce clarification and alimitedamount of decolorization in addition to neutralization. But foraverage use ne1ther step separately employed will be sufiicient.

economy by omission of the first fi tration, thus making the process atwo-stage, single filtration procedure. In this case, it is necessa-rybefore proceeding with the second stage to cool the mixture of oil, acidand clay to around 200 F. in order to prevent excess evaporation ofwater when the second-stage reagents are added and before these reagentshave had an opportunity to act on the oil. It is also necessar to usesomewhat lar er amounts of alkali t an when double filtration isemployed due to the large amounts of adsorbed acids in the first-stageclay. According to this modification the amount of alkali would beincreased in general to about 0.35%, or in particular cases up to about1.0%. This phase of the process is valuable from the standpoint ofeconomy and is good for certain types of oil.

It is also within the scope of the'invention,

to operate upon an alkaline oil, that is an oil containing soaps, bytreatin with clay and a dilute acid, for example oxalic acid as beforestated, to assist in the removal of the soaps present and to tend towarda product of low ash content.

Throughout the specification and claims where either of the terms clayand earth is employed, the same is intended to include any clay, fullersearth, other mineral earth or the like suitable for such purposes. Andwhere the term oil is used the same is intended to include oils, fats,waxes and oleaginous substances in general unless otherwise limited.Also it should be noted that the term alkali or caustic alkali isintended to include potassium hydroxide or the like as well as sodium hdroxide and that corresponding substitution may be made whereveradvantageous or desirable.

I claim:

1. The process of decolorizing and neutralizing o eaginous substancesincluding petroleum lubricatin oils, comprising commi'ngling the oilwith about 4 to 20 percent of raw clay together with water in amount aproximating half the weight of the clay, and acid'approximatin onequarterpercent of the substance treate heating, separating the clay, agitatingthe oil with about 4 to 16 percent of a fresh amount of clay, adding adilute alkali solution containing alkali less than one-half ercent ofthe substance treated, heating an removing the clay.

water and acid, the acid not substantially exceeding two percent of thewei ht of the oil, heating, removing the clay, ad in a second quantityof clay and dilute alka i solution containing alkali not substantiallyex- The above two-stage double filtration proclceedin one-half percentof the substance ess may be modified from the standpoint of treateheatin to drive 01f the water and removing the c ay.

' 3. The recess of decolorizmg and neutralizing o eag'mous substancesincluding petroleum lubricating oils, comprising treating oil with claand a dilute acid solution containing aci not substantially exceedingtwo percent of the oil, heating, removing the clay, adding a secondquantity of clay and treating with a dilute alkali lution containingalkali in amount not sub t antially exceeding onehalf percent of the oiland in the presence of a salt of an acid whose calcium salt issubstantially insoluble in water.

4. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising mixing clay with acid,treating oil therewith, and in a separate treatment treating the 011-with clay and an alkali solution.

5. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising com mingling oil with anacid and clay, removing the clay and adding to the oil a second quantityof clay, together with an alkali solution.

6. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprisingmixing an oil with clayand a strong acid and then treating the oil with clay and an alkalisolution.

7. A process of decolorizing and neutralizing petroleum lubricating oilscomprising mixing the oil with clay, acid and water, heating below theboiling point of the oil to vaporize the water and treating the oil withclay and an alkali.

8. A process of decolorizing and neutralizing petroleum lubricating oilscomprising treating the oil with clay, a strong acid and water, heatingbelow the boiling point of the oil to decolorize the oil, removing theclay, and treating the oil with a second quantity of clay and an alkali.

9. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising commingling the oil withclay and a strong organic acid, and treating the oil with a secondquantity of clay and an alkali.

10. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising commingling the claywith oxalic acid, treating a quantity of oil therewith and treating saidoil with another quantity of clay and an alkali.

11. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising commingling clay with astrong organic acid and treating oil therewith.

12. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating a quantity ofoil with clay and oxalic acid.

13. A process of decolorizing and neutralizing petroleum lubricatingoils compristion, and heating below the boiling point of the oil toexpel excess water.

14. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising mixlng an oil with clayand a strong organic acid and heating to vaporize water and todecolorize the oil.

15. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising mixing an 01]. with clayand an oxalic acid solution and heating to vaporize excess water.

16. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treatlng an oil withclay and acid and with a second quantity of clay and a solution ofalkali, and heating, thereby vaporizing water and aiding decolorization.

17. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating an oil withclay and an acid, removing the clay, and then -treating the oil with asecond quantity of clay and an alkali solution sufficient to neutralizethe acid and heating, thereby vaporizing excess water.

18. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating an oil withclay and an acid, removing the clay and then treating the oil with clay,an alkali and an oxalate.

19. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating 'an oil withclay and an acid, removing the clay, and then treating the oil with asecond quantity of clay, an alkali and a salt of an acid whose calciumsalt is substantially insoluble in water.

20. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating an oil withclay and an alkali solution and vaporizing water by heating the mixture.

21. A process of decolorizing and neutralizing acid oleaginoussubstances including petroleum lubricating oils comprising treating anoil with clay and an alkali solution suilicient to neutralize the acidand heating, thereby vaporizing excess water.

22. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating an oil withclay, an alkali and an oxalate.

23. A process of decolorizing and neutralizing oleaginous substancesincluding petroleum lubricating oils comprising treating an oil withclay, an alkali and a salt of an acid whose calcium salt issubstantially insoluble in the mixture.

\ v ing mixing an oil with clay and an acid solu- 6 j i sane tralizingoleaginous substances including pesolution in quantity sufiicient toproduce a troleum lubricating oils comprisingmixm moist clay, mixing oilwith such moist clay, clay with an alkali solution, treating an o andheating the mixture thereby vaporizing with the mixture, vaporizingexcess Water by moisture from the mixture and producing a heating theoil mixture, and removing the good decolorization of the oil.

clay from the oil. 33. A process-tor refining petroleum oils 25. Aprocess for refining oils comprlslng comprising acid-treating the oil,then treatcommingling the same with cla in the presing the oil withalkali to neutralize the oil, ence of an alkali solution, heatlng saidmixestablishing an excess of alkali in the oil, as 10 ture to obtain agood decolorization and treating the oil with clay whereby the clayvaporizing water by such heating. acts upon the oil in the presence ofsaid excess 26. A process of treating oleaginous subof alkali, andheating the mixture to effect stances having acid reactions includingpetrodccolorization. leum lubricating oil comprising treating the 34. Aprocess for treating petroleum oils 70 oil with clay in sufiicientquantity to decomprising commingling the oil with a decolorize theoi'and at the same time subjectcolorizing clay in decolorizing quantitiesand ing the 011 and clay to the actlon of a caustic with an alkalisolution n the presence of thereby vaporizing at least a substantial themixture by heating and thereby eifecting 76 quantity of the water of thesolution. good decolorization.

2?. A process of decolorizing and neu- 35. A process of treatingoleaginous sub- 2 alkali solution, and heating the oil While in alkalisolution containing water approximatcontact with said solution andthereby exing the amount of the clay. pelling water and producingdecolorization. 36. A process of producing decolorized 28. A process ofproducing decolorized oleaginous substances including petroleumoleaginous substances including petroleum lubricating oils comprisingtreating an oil 86 lubricating oils comprising treating an oil with clayand a dilute alkali solution in the with clay and a dilute alkalisolution in the presence of each other, said solution containpresence ofeach other, said solution containing water sufficient to wet the clayandinsurc ing water suflicient to wet the clay and m good contact of theclay with the ,oil, but insure good contact of the clay with the oil,sufficient to cause agglomeration. 9o 35 but insufficient to causeagglomeration, and 37. A process of refining oil which comvaporizingwater from the mixture by heatprises the stepsof treating oil with analkali ing the same. solution and contacting the alkaline oil con- 29. Amethod of refining acid petroleum taining excess of alkali solution withclay oils comprising the steps of subjecting the oil and removing theclay. v 40 to the action of clay in contact with a Water 38. A processof refining oil which comsolution of alkali suflicient to neutralize theprises treating acid oil with clay and adding oil, and heating themixture thereby vaporizan alkaline solution to the thus treated oil ingWater and effecting decolorization. and contacting the alkaline oilcontaining ex- 30. A method of refining petroleum oils cess of alkalinesolution with clay and removsteps of subjecting such acid oil to theaction 39. A process for treating oleaginous subof a decolorizingquantity of clay at the same stances including petroleum lubricatinoils, time with subjection of the action of an excomprising treating anoil with clay sui cient cess of alkali solution, and heating the mixtodecolorlze the oil and in the presence of ture to effect decolorization.an alkali solution containing water amount- 31. A process according toclaim 30 whereing to between one half and twice the amount in alkali ispresent in the form of a water of the clay.

solution thereof and the heating is carried on SIgned at Oleum, 1n thecounty of Contra to produce vaporization of the water. Costa, and Stateof California, this 7th day 11 55 32. A process for treating petroleumoils of January, A. D. 1926.

comprising commingling clay with an alkali 'DAVID R. MERRILL.

